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Topsoil
Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Description Topsoil is composed of mineral particles and organic matter and usually extends to a depth of 5-10 inches (13–25 cm). Together these make a substrate capable of holding water and air which encourages biological activity. There are generally a high concentration of roots in topsoil since this is where plants obtain most of their vital nutrients. It also plays host to significant bacterial, fungal and entomological activity without which soil quality would degrade and become less suitable for plants. Bacteria and fungi can be essential in facilitating nutrient exchange with plants and in breaking down organic matter into a form that roots can absorb. Insects also play important roles in breaking down material and aerating and rotating the soil. Many species directly contribute to the health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsoil
Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil, it is composed of a variable mixture of small particles such as sand, silt and clay, but with a much lower percentage of organic matter and humus, and it has a small amount of rocks which are smaller in size mixed with it. The subsoil is also called B Horizon. Whereas the topsoil (alternatively called the A horizon) tends to be the site containing the greatest physical, chemical, and biological activity, the subsoil (or the B horizon) is the region of deposition where you can find iron oxide, clay particles, and small amounts of organic material reaching from the A horizon. It is also less weathered than the topsoil. Due to human activity, the topsoil and subsoil in many environments has been mixed together. Below the subsoil is the soil base (or C horizon). Clay-based subsoil has been the primary source of material for adobe, cob, rammed earth, wattle and daub, and other earthen constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Horizon
A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. 'coarser' or 'sandier' than the horizons above and below. The identified horizons are indicated with symbols, which are mostly used in a hierarchical way. Master horizons (main horizons) are indicated by capital letters. Suffixes, in form of lowercase letters and figures, further differentiate the master horizons. There are many different systems of horizon symbols in the world. No one system is more correct—as artificial constructs, their utility lies in their ability to accurately describe local conditions in a consistent manner. Due to the different definitions of the horizon symb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former term specifically to displaced soil. Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil is a three-state system of solids, liquids, and gases. Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humus
In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Latin word for "earth" or "ground". In agriculture, "humus" sometimes also is used to describe mature or natural compost extracted from a woodland or other spontaneous source for use as a soil conditioner. It is also used to describe a topsoil horizon that contains organic matter (''humus type'', ''humus form'', or ''humus profile''). Humus has many nutrients that improve the health of soil, nitrogen being the most important. The ratio of carbon to nitrogen (C:N) of humus commonly ranges between eight and fifteen with the median being about twelve. It also significantly affects the bulk density of soil. Humus is amorphous and lacks the "cellular cake structure characteristic of plants, micro-organisms or animals". Description The primary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potting Mix
Potting soil or growing media, also known as potting mix or potting compost (UK), is a substrate used to grow plants in containers. The first recorded use of the term is from an 1861 issue of the ''American Agriculturist''. Despite its name, little or no soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ... is usually used in potting soil. Materials Materials used for growing mediums include: peat, coconut coir, wood products like bark and wood fiber, perlite, Mineral wool, stone wool, soils/tufts, and recycled paper and cardboard. Other materials used include rice hulls, sand, vermiculite, and calcined clays. Properties Typical potting mixes include one or more materials which retain moisture, one or more materials which aid in aeration and drainage, and fertilizer. Moisture-r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BSI Group
The British Standards Institution (BSI) is the national standards body of the United Kingdom. BSI produces technical standards on a wide range of products and services and also supplies certification and standards-related services to businesses. History BSI was founded as the Engineering Standards Committee in London in 1901.Robert C McWilliam. BSI: The first hundred years. 2001. Thanet Press. London It subsequently extended its standardization work and became the British Engineering Standards Association in 1918, adopting the name British Standards Institution in 1931 after receiving a Royal Charter in 1929. In 1998 a revision of the Charter enabled the organization to diversify and acquire other businesses, and the trading name was changed to BSI Group. The Group now operates in 195 countries. The core business remains standards and standards related services, although the majority of the Group's revenue comes from management systems assessment and certification work. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Carolina Department Of Agriculture And Consumer Services
The North Carolina Department of Agriculture & Consumer Services (NCDA&CS) is a state agency of North Carolina headed by the Commissioner of Agriculture. It is headquartered in the Agriculture Building in Raleigh. History In 1860, North Carolina Governor John W. Ellis encouraged the establishment of a board of agriculture in the state, but the North Carolina General Assembly—concerned about the possible outbreak of civil war—ignored his request. In 1868 North Carolina ratified a new constitution which provided for a Bureau of Statistics, Agriculture, and Immigration within the Office of the Secretary of State. Farmers continued to desire an independent agriculture department, and in 1875 the constitution was amended to allow the General Assembly to create an independent Department of Agriculture, Immigration, and Statistics "under such regulations as may best promote the agricultural interests of the State and shall enact laws for the adequate protection and encouragement o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Saturation
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. This is one of the ways that solid materials in soil alter the chemistry of the soil. CEC affects many aspects of soil chemistry, and is used as a measure of soil fertility, as it indicates the capacity of the soil to retain several nutrients (e.g. K+, NH4+, Ca2+) in plant-available form. It also indicates the capacity to retain pollutant cations (e.g. Pb2+). Definition and principles Cation-exchange capacity is defined as the amount of positive charge that can be exchanged per mass of soil, usually measured in cmolc/kg. Some texts use the older, equivalent units me/100g or meq/100g. CEC is measured in moles of electric charge, so a cation-exchange capacity of 10 cmolc/kg co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runoff Of Soil & Fertilizer
Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock market term * Runoff curve number, an empirical parameter used in hydrology * Runoff model (reservoir), a mathematical model describing the relationship between rainfall and surface runoff (see below) in a rainfall catchment area or watershed * Runoff voting system, also known as the two-round system, a voting system where a second round of voting is used to elect one of the two candidates receiving the most votes in the first round ** Instant-runoff voting, an extension or variation of runoff voting where a second round can be rendered unnecessary by voters ranking candidates in order of preference * Run-off area, a racetrack safety feature * Surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-cut
In civil engineering, a cut or cutting is where soil or rock from a relative rise along a route is removed. The term is also used in river management to speed a waterway's flow by short-cutting a meander. Cuts are typically used in road, rail, and canal construction to reduce the length and grade of a route. Cut and fill construction uses the spoils from cuts to fill in defiles to cost-effectively create relatively straight routes at steady grades. Cuts are used as alternatives to indirect routes, embankments, or viaducts. They also have the advantage of comparatively lower noise pollution than elevated or at-grade solutions. History The term ''cutting'' appears in the 19th century literature to designate rock cuts developed to moderate grades of railway lines. ''Railway Age's Comprehensive Railroad Dictionary'' defines a cut as "a passage cut for the roadway through an obstacle of rock or dirt." Creation Cuts can be created by multiple passes of a shovel, grader, scrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulvic Acid
Humic substances (HS) are organic compounds that are important components of humus, the major organic fraction of soil, peat, and coal (and also a constituent of many upland streams, dystrophic lakes, and ocean water). For a long era in the 19th and 20th centuries, humic substances were often viewed through a lens of acid–base theory that described humic acids (HA), as organic acids, and their conjugate bases, humates, as important components of organic matter. Through this viewpoint humic acids were defined as organic substances extracted from soil that coagulate (form small solid pieces) when a strong-base extract is acidified, whereas fulvic acids (FA) are organic acids that remain soluble (stay dissolved) when a strong-base extract is acidified. The remaining alkali-insoluble part of humus would be termed humin. Humic matter in isolation is the result of a chemical extraction from the soil organic matter or the dissolved organic matter and represent the humic molecules dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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